So if you do go for an EV cert, go for the one that has the best listed uptime on it's CRL or OCSP servers.
Having said that, I would never spend more than $10 on a cert, and just use the most standard/common "bundled" CA cert. No one will ever know. It will have faster page loads. And those fake stories that EV certs increase conversions are exactly that, fake, and misleading. No one will real world experience has ever claimed to see a positive difference with EV certs.
The only problem with cheaper certs is you have to bundle the intermediary CA certs...
http://www.devside.net/wamp-server/installing-comodo-positiv...